Air-feed for pulverized fuel.



s. H. HARRISON. AIRFEED' FOR PUL-VERIZED FUEL.

A APPLICATION FILED JUN E 5.1915. 4 11,155,725.) Patented Qct. 5,1915

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SIMON HENRY HARRISON, OF EASTON, FENNSYLVANIA,

AIR-FEED FOR PULVERIZED FUEL.

Application filed June 5, 1915. Serial No. 32,282.

T all whom it may concern:

Be it known that I, SIMON IIENRY HARRI- soN, a citizen of the United States, residing at Easton, in the county of Northampton and State of Pennsylvania, have invented a certain new and useful Air-Feed for'Pulverized Fuel, of which the following is a specification.

The purpose of my invention is to give rotarial motion to an injecting tube of air or steam used to convey surrounding pulverized fuel.

A further purpose of my invention is to whirl an interior injecting tube of air or steam delivered in advance, of pulverized fuel to be fed and to admit air behind the point of fuel admission.

A further purpose of my invention, is to regulate thewidth of annulus of admission for a tube of air or steam in advance of means for whirling the tube and to feed pulverized fuel outside of the tube and behind the point of delivery of the tube.

A further purpose of my invention is to provide spring balance in a conveyer for the pressure of injector air upon the rear of an axially movable valve.

Further purposes of my. invention will appear in the specification and claims'hereof.

have preferred to illustrate my inveution by but one form thereof among the various forms in which it may be embodied, selecting a form which is practical, eflic ent and inexpensive and which at the same tlme well illustrates the principles of my invention.

Figural is a side elevation partly in cen- ..tral longitudinal section, showing the preferred form of my invention. Figs. 2 and 3 are transverse sections of the structure shown in Fig. 1, taken upon lines 2-2 and 3 3, respectively, and looking, in the directions of thearrows. Fig. 4 isa fragmentary section of a modification, corresponding in position to Fig. 1..

Similar numerals of reference indicate like parts in the drawing The most advantageousinjection of pul- I verized fuel for burning must'satis-fy two types of requirement. It must physically convey the fuel to the required point, and it must intimately and uniformly mix the correct proportion of conveying fluid with the fuel. The conveying fluid will be referred to as air herein, for convenience.

From the conveying standpoint merely,

Specification of Letters Patent.

Patented Oct. 5, 1915.

these have been more successful than from the standpoints of economy and intimacy and uniformity of mixing. In some of them conveying was the sole object. As conveyers merely, extra air supplied by them is not in urious; only wasteful. But with the varying proportions of air required per unit of fuel at the different volumes of feed that may be required an excess of air may be unavoidable with these prior forms which will be objectionable in the furnace, and unequalmixing of fuel and air is always objection.- able. Additional air can, of course, always be supplied but. permissible economy of H11 and excellence of mixing are necessar ly much sought for in pulverized fuel feed and r are characteristic of my invention.

I w liirl an interior regulable tube of conveying air, that which performs all of'the conveying work, so that its initialengagement' with the surrounding fuel shall be helical and the centrifugal component of the air shall have the highest efliciency in mixing the air with the fuel.

The air pipe 5 is shown as valved at (land as tapering at 7 and terminating in a nozzle 8 spirally fluted at 9 or ribbed at 10, 'as it may be viewed, upon the inside.

The nozzle casinglor shell 11 connected with a conveyer 12. The shell provides an annular space about the nozzle for receipt of pulverized fuel discharged, preferably, by a forced feed through pipe 13.

At the rear of the casing or shell I provide a valve, shown as of grid form, comprojects within a conveyer prising an annulus having a series of ant nular'ly distributed apertures 1-1 in the rearof the casing registering in full open position with apertures 15 in a movable Ering'16. The ring is shown as turned toi partly close the apertures. This general form of valve is,- of course, well known and needs no further description.

. Admission of air at the rear of the fuel inlet will take place whenever a partial vacuum is formed in the. casing and at a rate proportionate to the extent of vacuum. This air admission. at this point is in itself also well' known but Ibeli'eve has not previthe correspondingly arranged ously been used in combination with a whirling feed. It assists in'the mixing as the air there entering-passes through the fuel.

Since thespiraIing effect of the nozzle upon the conveying air is greatest upon the outside of the flowing air it attains a maximum when the air .is passed through the nozzle as a thin tube.- I secure this result by a circular valve 17 closing the'greater part of the width of the pipe or nozzle and longitudinally movable to adjust the size of the annular opening. The fineness of adjustment secured depends, in part, upon the taper of the pipe at 7. Obviously, any desired range of opening or complete closure 1 can be secured.

. The valve 17 is shown as mounted upon a stem 18 which is supported by the walls of the bore 19 of a spider 20; The rod is spring- .here screw 21, by which the valve, through the valve stem, extended at 22, is retained in adjusted position. An indicator, as 23,

maybe used to show the extent of opening.

The spring pressure is obtained by a spiral spring 24: pressing against the spider at one end and against a collar 25 upon the stem at its opposite end.

The interior of the nozzle and interior tapered surface of the pipe are shown in Fig. 1 as presenting an uninterrupted interior surface, which would require considerable movement of the valve to close it completely. Where it is desired to use the valve 17 for complete closure of the pipe or noz- .zle without so much movement, the nozzle may berelatively contracted to present a shoulder 26, as'm Fig. 4, against which the edge 27 of the valve may seat. This presents an advantage in offering a convenient means of determining a minimum opening before complete closure (the difference between the radius of the valve and the radius of the pipe just back of the nozzle) to carry the estimated minimum fuel feed, but is slightly disadvantageous in setting up cross air currents which tend-to scatter the air of the tube and reduce the effect of the spiraling.

The casing may be cleaned by opening door 28.

It will be evident that I obtain an interior spirally directed feeding air tube with fuel exteriorly fed to it and induced air entering at'the rear of the fuel, and that this desirable result may be obtained by other constructions and arrangements within the spirit and scope of my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is v 1. In a fluid feed for pulverized fuel, a casing having an inlet for pulverized fuel, a nozzle terminating in the casing in advance of the inlet, an air supply pipe connected with the nozzle, a valve transverse to the axis of the pipe, a stem for the valve, :3. guide for the stem and a spring pressing the stem away from the nozzle.

2. In a fluid feed for pulverized fuel, a casing, an inlet for fuel entering the casing, an interiorly spiraled nozzle within the casing, a tapered air feed pipe connected therewith, a valve for the air extending transversely to the axis of the nozzle, a stem for the valve, a support for the stem guiding it in movement parallel to the axis of the pipe and means for securing the stem inadjusted position.

3. In a fluid feed for pulverized fuel, a casing having an inlet for pulverized fuel, a nozzle terminating in the casing in advance of the inlet, a tapered air supply pipe connected with the nozzle, a valve transverse to the axis of the pipe, a stem for the valve, a guide for the stem and a spring pressing the stem away from the nozzle and approximately equalizing the pressure of the air upon the rear of the valve.

4. In a fluid feed for pulverized fuel, a casing having an inlet for pulverized fuel and air openings in the rear thereof, a nozzle terminating. in the casing in advance of the inlet and having a spiraled interior, an

7 air pipe connected to the nozzle and a valve in the pipe giving an annular opening between it and the pipe.

SIMON HENRY HARRISON.- Witnesses:

FLORENCE E. BARBEREY, HELEN M. AGKERMAN. 

